Lighting system, track and lighting module therefore

ABSTRACT

A lighting system comprising a track having a first and a second rail ( 5, 7 ), mutually extending equidistantly. Said first and second rail comprise a first respectively a second electrically conductive strip, mutually electrically isolated. A lighting module ( 17 ) comprising a first and second electrical contact, which lighting module in mounted position rests by gravitational force on the first and second rail. When mounted the first and second electrical contact are in electrical contact with a respective one of the first and second electrically conductive strip. The lighting module is dismountable from the track by a single displacement of the lighting module in a direction against the direction of the gravitational force.

FIELD OF THE INVENTION

The invention relates to a lighting system comprising a track and alighting module. The invention further relates to a track and a lightingmodule.

BACKGROUND OF THE INVENTION

In retail and office environments it is common practice to usetrack-based systems to build the lighting system. These tracks can besuspended or recessed into the ceiling. To these tracks, lamps can beattached. Different types of these tracks are available. Some work with230V but there are also lower voltage versions that enable differenttypes of lamps to be used with the track. The track acts as a conductorof electricity and as a means to attach the lamps to. The lamps areusually mounted using some sort of clip. The main advantage oftrack-based systems is the flexibility it offers. It allows building aninfrastructure of tracks which then allows lamps to be placed underneaththe infrastructure of tracks built into that space.

Within the domains of architecture and interior decoration there is aclear trend towards unobtrusiveness. This also has implications orrather opportunities for the lighting domain in that within the retailand office environments there is a clear trend towards unobtrusivelighting systems. Track systems are often used in these environments asthey offer a lot of flexibility. The tracks are used to build the basicinfrastructure for both the fixing and the powering of the lamps. Thereare a few disadvantages to this system i.e.:

With most current systems the lamps hang underneath the rail. In case ofa retail environment where oftentimes spots are used this means thatthere are a lot of high power (3000 lm) lamps are attached to the railand directed onto their targets (like shelves or mannequins). Thisresults in a visually disturbed picture: a rail with lamps hangingunderneath it all directed into different directions. This attractsundesirable attention, as the focus of the customers should be on theproducts that are for sale.

In current track based systems the light module is attached to the trackwith some sort of clamp. Attaching the lamp to the track or moving themodule is often difficult to do. It requires two hands and pressure fromthe hand to close or release the clamp and all of this above your headstanding on a ladder. Moreover, the clamp regularly also establishes theelectrical connection, so when the lamp can be moved the light is offand there is no feedback on the actual movement of the light-effect.This lack of ease-of-use limits the shop owner or lighting designer toadjust the lighting on the fly as they see fit after the system has beeninstalled. This for example would be desirable when the shop ownerdecides to move around some furniture when updating the store or when alamp needs to be replaced by another one which is more suitable in thenew situation.

Current track based lighting systems have lamps hanging underneath arail. This makes it difficult to light something on the ceiling as thiswill require the light to be redirected from a downwards direction intoan upwards direction. Furthermore, the strip itself will be in the lightpath, hampering a uniform or light projection on the ceiling.

Track based lighting systems having a pair of equidistant electricconductive (metallic) cables as rails for mounting of the lamps have thedisadvantage that said cables itself are not rigid and thus have to bemounted with great tension to give them some rigidity rendering theinstallation of such lighting system relatively complex and cumbersome.Furthermore, the tensioned, equidistant cables are still susceptible tovibrations and/or moving apart already by relatively small forces. Thisgenerally is counteracted by connecting the equidistant cables bybridges, but then these bridges need to be spaced apart at such smalldistances that the free moving and positioning of lighting modules onsaid track are significantly hampered.

As mentioned above, in modern lighting systems there is a need to have agreat deal of flexibility in the user's ability to easily control thequantity, direction, and characteristics of the light emitted from thesystem. In theater settings, one is accustomed to observing a number oflight fixtures capable of directing light of varying intensities, color,and other characteristics onto the stage. In commercial settings,adjustable reflector lamps and track lights are frequently employed toilluminate merchandise or displays. In office and residential settings,track lights are typically used to direct light to a particular workarea or for visual effect. In applications where the appearance of thelighting system itself contributes to its overall aesthetics, there areadditional design and production costs. A lighting system comprising atrack with a removable lighting module and fulfilling the abovementionedissues is known from U.S. Pat. No. 7,806,569. In the known lightingsystem the lighting module is mounted on a track by an attractive forcebetween magnetic material of the light module and magnetic material ofthe track such that a light module may be installed on, removed from, orrelocated on the track manually without tools or permanent electricalconnection.

Yet this known system has disadvantages. One disadvantage is that whilethis system is flexible, it still is cumbersome to adjust for differentlighting requirements due to the presence of relatively high permanentmagnetic forces intended to hold the lighting module in fixed positiononto the track. When the lighting system is used to fit in falseceilings, the lighting module suspends from said track and is attachedto it only by magnetic force, said force must thus be high enough toprevent the relatively lighting module to detach from the track, evenduring shocks. Another disadvantage of the known lighting system is thatthis it is relatively costly because of the use of (relatively strong)magnetic materials to hold the relatively heavy lighting module. Yetanother disadvantage of the known system is that an incidental drop ofthe lighting module involves the risk of breakage of the lamp.

Finally, there is the disadvantage of the known lighting system that itis obtrusive due to the lighting module protruding from the track. Asthe lamps hang underneath the track, the rail itself will be in thelight path, hampering a uniform or light projection on the ceiling.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a lighting system of thetype as described in the opening paragraph in which at least one of thedisadvantages is obviated. The object is accomplished by a lightingdevice comprising:

a track comprising at least a first and a second rail mutually extendingequidistantly along an axis, said first and second rail are spaced apartby an opening defining a plane P and the first rail comprises a firstelectrically conductive strip and the second rails comprises a secondelectrically conductive strip, said strips are mutually electricallyisolated,

at least one lighting module comprising a first and second electricalcontact adapted to make electrical contact with a respective one of thefirst and second electrically conductive strip when supported by arespective carrier side of both the first and the second rail, andcomprising a base having a mutually opposing first and second side,

the lighting module and track being free from mutual overhang to enableto dismount the lighting module from the track by a displacement in adirection essentially perpendicular to plane P,

wherein the track comprises the light source, preferably the lightingmodule has a light incoupling surface facing towards the light sourceand light outcoupling surface at its first side. Said light incouplingsurface could be the same as the transverse side wall of the base inwhich contact pens are resiliently seated. The light source can emitlight into the lighting module or emit light towards a light redirectionelement, for example a reflector or refractive body to redirect thelight into a target direction. Due to their relatively small size, LEDsare in particular suitable to be located in the track. LEDs offer muchmore design freedom to design lighting systems and luminaires comparedto luminaires designed to accommodate conventional light sources as, forexample, halogen incandescent lamps, fluorescent lamps, and highpressure gas discharge lamps. Also LEDs are becoming more efficient andcheaper very rapidly. This leads to a future situation where the LEDswill only account of a small portion of the Bill Of Material (BOM)compared to the dominant position they hold right now Thinking along thepath of “LEDs for free” offered a few new ways of applying LEDs toanswer to the need for flexible systems in a new way.

With flexible rail-like systems there always is a trade-off betweenwhich components go in which part of the system. For example,electronics, optics, mechanics etc. Usually the LEDs and sometimes thedriving electronics are integrated into the lighting module. Thesecomponents/parts use up a certain amount of space. In this embodiment ofthe lighting system of the invention, a system is proposed in which theLEDs are located in the side of the rail instead of being located in thelight module, preferably in combination with the use of waveguides,optionally with out-coupling particles mixed in them, to direct thelight to target locations in the ambient space. This embodiment enablesthe possibility of relatively thin designs, cheap and passive moduleswhich can be exchanged easily by the user. Because the modules are sosimple it is relatively cheap to develop many different ones whichenrich the flexibility of the system from a users' utility point ofview. A further cheap embodiment of the lighting system is characterizedin that the optic plate is provided with light outcoupling pattern at atleast one of its first and second side.

Generally the track extends in a flat manner in plane, though slightlycurved, out of plane, tracks are possible as well and do all within thescope of this invention. The lighting system according to the inventionoffers a more unobtrusive lighting system keeping the of the known trackbased systems while at the same time taking away some of thedisadvantages of said known track lighting systems. The opening inbetween these two rails defines the space available for the module. Themodule fits exactly within the space defined by the two rails. Thisallows for the integration of the lamps into the track rather thanhanging them underneath the track. Furthermore said opening enables toposition office infrastructure elements, for example air conditioningmeans sprinkler means and smoke/fire detectors, in an unobtrusivemanner.

This rail provides space for the module to emit light directed towardsthe top, from the top of the module and emit light directed towards thebottom from the bottom side of the module. Also different types lightmodules can be made that allow light to be emitted under an angle andre-directable. Therefore this rail allows for multiple types of lightmodules (up and down light for instance). Also sensors can be integratedin the top and the bottom of the module reaching an almost 360-degreesensing view. Also if necessary these modules can be much longer thantraditional lamps as they can stretch along the rail.

In the lighting system according to the invention the lighting modulerests on the track essentially only by gravity forces so that a lightingmodule may be installed on, removed from, or relocated on the trackmanually without tools or without necessarily being permanentlyelectrically connected. The lighting module and track being free frommutual overhang to enable to dismount the lighting module from the trackby a displacement in a direction essentially perpendicular to plane P,i.e. can be taken out from the track in a direction transverse to planeP, for example in a direction against gravity, without finding anyblocking or hampering parts, for example an interlocking structure or aresiliently structure that needs to maneuvered around or bend to freethe way. This system is flexible and adjustment for different lightingrequirements is simple. To counteract the lighting module to fall fromthe track, the rails on which the lighting module rests, could beprovided with ridges that limit sidewise movements of the lightingmodule and keep it on the strips. As magnetic materials are obsolete inthe lighting system of the invention for fixation of the lighting moduleon the track, the lighting system is relatively cheap, yet magneticmaterials still can be applied in the inventive lighting system, forexample to keep the module on the rail(s), to counteract mutualcollision or too close proximity of lighting modules present on the samestrips of the track. However, as the module has not to be solely carriedby the magnetic force, the magnetic force in this case could berelatively small, in particular when the lighting modules are carried onwheels and lighting modules can roll practically frictionless over therails/track. The relatively small magnetic force then hardly hamperseasy dismounting of the module from the strips.

US20110199790A1 discloses fixing brackets as a first and second railmutually extending equidistantly along an axis and comprising a first,respectively a second mutually isolated electrically conductive stripand comprising a light source.

US20120287671A1 discloses a light guide comprising a first and secondelectrical contact and a base with a mutually opposing first and secondside.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further elucidated by means of the schematicdrawings in which the dimensions of some features might be exaggeratedfor clarity and which drawings by no means are to be taken as to limitthe scope of the invention, but rather to illustrate the amplepossibilities of the invention. In the drawing

FIG. 1 is a perspective bottom view of a first embodiment of thelighting system according to the invention;

FIG. 2 is a perspective top view of the lighting system of FIG. 1;

FIG. 3 shows cross sections of some profiles of rails of tracksaccording to the invention;

FIG. 4 shows a cross section of a second embodiment of the lightingsystem according to the invention;

FIG. 5 shows cross sections of a third embodiment of the lighting systemaccording to the invention;

FIG. 6 shows an undulated version of the track of the lighting systemaccording to the invention;

FIG. 7 shows two lighting systems being mutually coupled by a lightingmodule according to the invention;

FIGS. 8A-D shows two tilts of two embodiments of a lighting module on atrack of a lighting system according to the invention;

FIG. 9 shows different shapes of a light guiding base part of thelighting module according to the invention;

FIG. 10 shows a fourth embodiment of a lighting module according to theinvention in perspective and partly in cross-section;

FIG. 11 shows a perspective top view of a capacitive coupled lightingmodule flexibly mounted on the track;

FIG. 12 shows a coated track suitable for capacitive energy transfer toa lighting module;

FIG. 13 shows a fifth embodiment of the lighting system according to theinvention with the light sources located in the track;

FIG. 14 shows a detail of a rail provided with the light sources mountedon a PCB of FIG. 13;

FIG. 15 shows a bottom view of a lighting module with an alternativelight guide base part suitable for use in the lighting system of FIG.13;

FIG. 16 shows an embodiment of the anode and cathode strip being locatedin different rails and an embodiment of a lighting module connectingthese strips;

FIG. 17 shows an electric scheme for parallel mounted arrangement of aplurality of lighting modules or light sources on the track;

FIGS. 18A-B shows a cross-section of the constructions of a reed-contactand sensor as located in the rail(s);

FIG. 18C shows an electric scheme of the lighting system for control ofthe various lighting modules/light sources;

FIGS. 19A-B shows both top views and transverse cross-sections of twodifferent light guide base parts of lighting modules;

FIG. 20 shows a perspective view of a sixth embodiment of the lightingsystem according to the invention;

FIG. 21 shows a general, basic lighting system according to theinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention and advantageous embodiments will be generally describedat the hand of the basic, general FIG. 21. A subsequently more detaileddescription of the advantageous embodiments will be done at the hand ofFIGS. 1 to 20.

FIG. 21 shows a schematic top view of the basics of the lighting system1 according to the invention. The lighting system comprises a track 3comprising a first 5 and a second rail 7 extending mutually parallelalong an axis or length axis 9. The first and second rail are spacedapart by an opening 11 lying in a plane P as defined by the parallelextending first and second rail. If the first and second rail areslightly curved, i.e. that the first and second rail together bendslightly out of a flat plane upwards or downwards, then the plane P isconsidered locally and follows the curvature of the first and secondrail. Both the first and second rail can electrically contact a lightingmodule 17 when it is mounted on the track. In mounted position the firstside of the lighting module rests with gravitation force on the trackand is dismountable therefrom by a simple displacement of the lightingmodule in an upwards direction against the gravity direction 45. Theopening is large enough to access the lighting module by hand from belowfor lifting the lighting module and to pass it through the opening andthrough plane P to below the track.

The two rails (that make up the track) are not only used to carry themodules but also are used to electrically connect with the modules andto position the modules. The two rails can be formed in such a way thelight module “falls into place” as it is forced by gravity and the slopeof the rails. A truncated, open wedge is one of the shapes that providessuch function. The track of the lighting system is rigid, such that itwill not deform or have only neglectable deformation, i.e. deformationwhich is insignificant for its functioning, under its own weight andalso will also have neglectable deformation under gravitational forcesexerted by the load of the lighting modules.

The electrical contacting of the module to connect to the rails can bedone in multiple ways. For example, by using good conductors like copperto make the rail from, power can be delivered to the modules placed inthe rail through galvanic connection. Also other mechanisms of powerdelivery can be used like capacitive power transfer not requiring agalvanic connection between the rail and the modules. The combination ofthe shape of the parts that make the rail with the ability to transferpower makes it very easy to install modules by dropping them in from thetop or by sliding them in from the bottom.

A range of different light modules can be envisioned. These can be morelike the traditional down lighters or spots. But they can also be moreadvanced lamps that have been optimized for a particular light qualitye.g. color rendering, texture rendering or modeling. Also light cancontribute to the atmosphere of the space. Pre-set light modules can bemade with pre-designed optics that will create the most beautifulatmosphere-enhancing patterns on the walls. Also dynamic light modulesthat are connected to the internet or have an embedded sensor becomewithin the range of possibilities. Because it's easy to replace them,they almost become ‘physical light apps’.

An embodiment of the lighting system is characterized in that thelighting module is passable through plane P via said opening. When thetrack is mounted in a false ceiling and flush with other ceiling tiles,then the strips are only directly accessible from one side, i.e. frombelow the ceiling. This embodiment of the lighting system isparticularly convenient as exchange or addition of lighting modules isthen simplified, i.e. it is not necessary to temporarily remove otherceiling tiles to have access to the strips of the lighting system.

An embodiment of the lighting system is characterized in that thelighting module is essentially planar and/or that the first side of thelighting module is essentially flush with the first and second rail. Thelighting module thus does not protrude from the track/strips and thuscleaning of the lighting system is simplified, moreover the risk onincidentally hitting a protruding lighting module and its possiblesubsequent fall from the track is reduced, for example when the systemis applied in false ceilings, and the lighting system and/or the firstside of the lighting module is flush with the ceiling tiles.Furthermore, the unobtrusiveness of the lighting system is improvedthereby.

An embodiment of the lighting system is characterized in that the firstand second electrical contact are provided at the first side of thelighting module and that the first and the second electricallyconductive strip are provided at the carrier side of the firstrespectively the second rail. In the standard installed orientation ofthis embodiment of the lighting system an easy mounting of the lightingmodule and mutual electrical contacting of strips and module is simplyattained and maintained by gravitational force, thus enabling a verysimple construction and desired adjustment of the lighting system.However, this embodiment involves the risk that it could be susceptibleto dust collection on the electrically conductive strips. Said dustcollection might negatively influence the reliability of mutualelectrical contact between the electrical conductive strips and theelectrical contacts of the lighting module. To counteract dustcollection an embodiment of the lighting system is characterized in thatfirst and second electrical contact are provided at a side faceextending from the first side towards, and optionally connecting, thesecond side and that the first and a second electrically conductivestrip are provided on the rail at a respective rail wall extending fromthe carrier side normal to plane P along the axis. In the normalinstalled orientation of the lighting system the electric conductingstrips are vertically oriented and less susceptible to dust collection,thus reducing the risk on deterioration or degradation of establishingelectrical contact with the lighting module. To further enhance thereliability of the mutual electrical contact between strips and themodule an embodiment of the lighting system is characterized in that theelectrical contacts are slightly magnetic, resilient and/or resilientlyseated in the base, preferably in a transverse side wall of the basefacing towards a respective one of the first and second rail.Furthermore, when the electrical contacts are located at the side facethis renders the lighting system to have the advantage to enable tohorizontally turn the lighting module over 180° and yet the module toelectrically connect to the strips.

An embodiment of the lighting system is characterized in that thelighting module comprises the light source. The lighting system can befurther characterized in that the lighting module with the baseaccommodates the light source and has at least one light emission windowin at least one of the first and second side. In these embodiments thelighting module is considered to be a lamp in which the first and/or thesecond side of the lighting module has a second light emission window.It is thus enabled turn the lighting module upside down (or in otherwords: flip 180° over a horizontal axis) and thus to switch between, forexample, upward lighting and downward lighting or thus to simply switchbetween beam characteristics, like narrow beam and broad beam, or toswitch between a beam directed to the left and directed to the right.Alternatively, for enabling the lighting module to flip and electricallycontact with the strips, it is possible that the module has electricalcontacts on both the first side and the second side.

The resiliency of the electrical contacts could come from the contactsitself being made as springs or come from the electrical contacts beingresiliently seated spring pens. These pens push parallel to the lengthof the module. For example, the lighting module has four pens, two onboth sides. The profile of the module and the profile of the rail can beembodied such:

That both pins will push against the profile on both sides.

The profile of the rail is chamfered on the top so that the pins aregradually pushed into the module. This makes it easier to get them inbetween the two rails that make the strip.

The same chamfers can be found on the edges of the module and the rail.

There is a thin isolated layer of copper on the inside of the profileswhich become the conductors. One side is the anode, the other one thecathode.

Due to the internal springs the four pins push outwards. This couldcause the first and second rail to be pushed away from each other, thusincreasing the opening in between said first and second rail and thusenhancing the risk on the lighting module to fall. This can becounteracted, for example by:

By using an L or U profile, these profiles are more rigid because of theperpendicular walls along the edge of material when compared to anI-rail profile;

By using a chamfered slit inside the module that will force the moduleinto a defined distance to the conducting part (and thus pushing thepens inwards.

Though the pins' contact surface is small, it should be big enough toconduct the current. The small surface area has benefit when moving themodule along the length of the strip. The scratching will remove anydirt or corrosion.

An embodiment of the lighting system is characterized in that the railhas a cross section profile chosen from the group consisting of aU-profile, an L-profile, a concave curvature towards the lightingmodule, and a combination of the first and second rail forming awedge-shape. The first and second profiled rails are put together suchthat there is an opening in between for the lighting modules. Thelighting modules can, for example, be lamps, control, and power modules.The form of the rails could (partly) define the auto-positioning abilityof the lighting module. Different shapes and sizes of rails can be used.However, there are some considerations to be made with respect to theform of the rail which can be prioritized depending on the application.With some applications some of these features can be omitted. Inparticular these considerations are:

The form has to be such that the lighting module can be made within thedimensions of the rail;

The form has to be such that the ability to transfer power from the railto the lighting module is sufficient;

The module preferably should auto-center when dropped in from the top toenhance ease of mounting/installation;

To further enhance the ease-of use a mounted lighting module should beeasy to be removed, moved and placed on the track;

When the lighting module is mounted on the track, a permanent gravityforce pulls the lighting module downwards, the phenomenon that the firstand second rail could be pushed apart by said force, making the modulenot to be flush with the track but hang (slightly) below the track,preferably should be coped with;

Embodiments of the rail that have a surface facing (a least a bit)upwards, have the danger of accumulation of dust on the surface of theprofile, the possible impairment of the transfer of power shouldpreferably be handled;

To build a system of rails, the rails should be connected to each otherat least mechanically and possibly also include power transfer.

Such U-, L- and wedge-profiled rails counteract the risk on sidewisemovements of the lighting module and/or the rails and thus reduce therisk of the lighting module to fall from the track or to get off thestrips and loose electrical contact therewith. In particular, when thelighting module is provided with grooves that, in mounted position, griparound at least a part of a respective rail, for example as is presentin a U-profile or L-profile of the rails, has the advantage that it isnot removable from the rails and strips in a sidewise displacement,hence always keeps aligned with said strips. The module is onlyremovable from the rails and strips by a single displacement of thelighting module in a direction against the direction of thegravitational force. Furthermore, a sidewise movement of a single railor both rails/strips is also obviated due to the gripping action of themodule around (a part of) the rails. Additionally, this renders thelighting system to be more rigid as the module itself has the additionalfeature of acting as a bridge between the two rails. Optionally, thenumber of bridges could be reduced. The bridge function of the lightingmodule could be of particularly relevance when the track has anelongated shape along the axis. An elongated track enables the lightingmodule as such to be (freely) shiftable over said track along the lengthaxis over relatively long distances, but simultaneously the lightingmodule, when provided with rail gripping grooves, to act as bridges torender the elongated track to be more rigid. The opening in between thefirst and second rail can be used by the designer as they see fitdepending on the applications. In some cases it is desired to have thelighting module within the area defined by the upper and lower edges ofthe track/rails. In other cases it is also acceptable when the lightingmodules stick out a little bit. The lighting modules can be equippedwith standard light sources, but also side-emitting LEDs along with alight-guide are an option.

A specific embodiment of the lighting system is characterized in thatthe first and second rail are mutually axially aligned and together areshaped as a(n open truncated) wedge extending along the axis as aconsecutive connected sequence of insets. Said insets are built-up byin- and outwardly bulging parts of the wedge shaped track. When theseinsets match with the shape of the module, it is attained that themodule snaps into a predetermined place. This specific form of the trackand lighting module enables the track to be are put under an anglerelative to gravity or tilted along its axis (length direction) whilethe module will remain positioned in the inset, thus undesirable,automatic slide down of the modules is simply counteracted. Alternativeways to counteract said undesired slide-down are by making use of clampsor magnets.

The lighting module can also be designed to be re-directable within thetrack. This adapted shape of the lighting module, for example at leastpartly sphere-like, can be tilted within the wedge shaped track andtherefore be used to redirect the direction of the light. It is howeverimportant that the center of gravity is always in the center of theradius of the sphere or that the center of gravity moves to a positionright in between the rails and in the position set by the user.

An embodiment of the lighting system is characterized in that thelighting module is provided with grooves present on both the first andsecond side of the lighting module. This renders the lighting system tohave the advantage to enable to flip the lighting module and yet tomaintain the gripping of the module onto the rails and hence to maintainits bridging function.

An embodiment of the lighting system is characterized in that thelighting module is chosen from the group consisting of a power supply, avoltage power converter, a current source, a coupling module forcoupling two lighting systems, and a user interactive receiver pluscontrol module. The power demand of the modules can be different.Therefore we propose a system with a modular power system where thepower supplies are formed into the same form factor. That allows theuser to add power-supply modules to the system whenever necessary (morelight modules mean more power modules). Or replace a certain powermodule by another more powerful module. Using a module as a power supplyalso enables the user to add the power where there is a power socketavailable. The power supply can be dropped into the strip at any placeas well. This is especially a nice feature whenever a temporal showrequires more light locally and power can be moved from one area toanother easily. This ensures no conflict with overall power regulations(max power/feet²).

When the lighting module is a power supply, the lighting system isconnected to the mains via a power cable to the power supply enablingthat the average installed power of the lighting system is low, but theused power can be set higher by increasing the number of power supplies.For example, if one power supply lighting module supplies 25 Watt (W),and 50 Watt power is needed, then simply a second power supply module of25 W (with additional power cable to the mains, or optionally via thefirst power supply module) is added to meet the demand. To enable aflexible amount of installed (driving) power it is desired to equip orpower modules with a so called Automatic Current Balance (ACB). Thistechnique is known form the electronic industry where it functions inredundant power system. (20 amps is supplied by 2 sources of 10 amp, theACB takes care of an even load distribution). This technique can also beutilized to simply add power sources when more power is needed.Generally, the power supply module simultaneously is a power converterfrom AC mains to, for example, 12V or 24V DC, rendering the lightingsystem to be safe to humans.

The lighting system comprising rails and electrically conductive stripscould be considered to form the mechanic and electric infrastructure. Toenable the user to install the strips in whatever configuration theywant, it should be possible to connect the different parts of thestrips. This lighting module for example, comprises two module-partswith a cable in between. Both parts look the same and connect to thestrip. When the lighting module is a coupling module or “ferry” module,a very simple possibility is attained to electrically couple/decoupletwo lighting systems with proximate ends by placing/removing a couplingmodule at both said proximate ends.

When the lighting module is a current source this renders the lightingsystem to have the advantage that the voltage difference over the twostrips remains constant and that each power consuming lighting module,for example when the lighting module is a lamp, can tap the amount ofcurrent which is optimal for its light source(s), for example LED(s).This renders the advantage that the performance of a plurality oflighting modules that are lamps is mutually independent, and theadvantage of a robust set-up of the lighting system.

Next to the light and power modules also the application ofcommunication modules are an option. This type of lighting module can beadded to the system to allow external sources to connect to the lamps inthe systems such as remote controls or data-sources. It is veryconvenient for users when the lighting module is a user interactivereceiver and control module, this renders the lighting system to havethe advantage that the settings of the lighting system are easilyremotely adjustable.

People nowadays are hesitant when they want to replace a lighting modulefrom a conventional, known track or rail as it requires quite some forceand knowledge about the secure/release system. Also when removing thelamp it's better to have the lamp turned off when removing. Currently,the lamp will get very hot and when detaching sparks may fly (due to thehigh current). To prevent both issues it would be better to turn thelamp off before removing it. But that would turn the light off, whichmakes it harder for the user to see what the light effect looks like. Inthe lighting system according to the invention there are various ways tofix this. For example, a first solution is to turn of the module througha UI where the off signal is sent through the network. A second solutionis to make the module turn off automatically when it is approached by ahand. In turn the module can turn itself on when the hand is removed.This can be done with different types of sensors like IR sensors andproximity sensors.

An embodiment of the lighting system is characterized in that thelighting module has curved side walls. In particular, when the profileis concave curvature towards the lighting module, or a combination ofthe first and second strip has a wedge-shape, the lighting system hasthe advantage that in mounted position said lighting module rests withits curved side walls on the rail and being tiltable around the axiswhile staying electrically connected. The lighting module being tiltablerenders the lighting system to have the advantage to enable simple andcontinuous, in other words not in discrete steps, redirection and/oradjustment of, for example an issued spot light beam issued by thelighting module. When the lighting system is embodied as having at leastone light emission window tilted with respect to the side in which it ispresent the angle over which the beam can be redirected is enlarged by acombination of tilting the lighting module and rotation of the moduleover 180° around an axis perpendicular to plane P.

An embodiment of the lighting system is characterized in that the trackcomprises the light source and preferably that the lighting module has alight incoupling surface facing towards the light source and lightoutcoupling surface at its first side. Said light incoupling surfacecould be the same as the transverse side wall of the base in whichcontact pens are resiliently seated. The light source can emit lightinto the lighting module or emit light towards a light redirectionelement, for example a reflector or refractive body to redirect thelight into a target direction. Due to their relatively small size, LEDsare in particular suitable to be located in the track. LEDs offer muchmore design freedom to design lighting systems and luminaires comparedto luminaires designed to accommodate conventional light sources as, forexample, halogen incandescent lamps, fluorescent lamps, and highpressure gas discharge lamps. Also LEDs are becoming more efficient andcheaper very rapidly. This leads to a future situation where the LEDswill only account of a small portion of the Bill Of Material (BOM)compared to the dominant position they hold right now Thinking along thepath of “LEDs for free” offered a few new ways of applying LEDs toanswer to the need for flexible systems in a new way.

With flexible rail-like systems there always is a trade-off betweenwhich components go in which part of the system. For example,electronics, optics, mechanics etc. Usually the LEDs and sometimes thedriving electronics are integrated into the lighting module. Thesecomponents/parts use up a certain amount of space. In this embodiment ofthe lighting system of the invention, a system is proposed in which theLEDs are located in the side of the rail instead of being located in thelight module, preferably in combination with the use of waveguides,optionally with out-coupling particles mixed in them, to direct thelight to target locations in the ambient space. This embodiment enablesthe possibility of relatively thin designs, cheap and passive moduleswhich can be exchanged easily by the user. Because the modules are sosimple it is relatively cheap to develop many different ones whichenrich the flexibility of the system from a users' utility point ofview. A further cheap embodiment of the lighting system is characterizedin that the optic plate is provided with light outcoupling pattern at atleast one of its first and second side.

The main components of this embodiment of the lighting system compriseat least one rail with integrated LEDs and separate modules. The firstand second rails support the modules. The module comprises a lightguide, for example in the form of PMMA plates. Optionally the lightguide holds scattering particles which scatter the light in a diffuseway, or alternatively the light guide is a diffuse plate either by bulkproperties or a surface treatment, for example sandblasted.

In the rail+LED combination the possibility is enabled to built-in amechanism resulting in the behavior that when a lighting module, i.e.light guide plate becomes/is present a number of locally present LEDsare turned on and when the plate is removed or not present said LEDs areturned off. This behavior can be attained in different ways, i.e.:

via a conductive pattern on a PCB, this embodiment allows a dynamicdefinition of the circuit;

via the detection of the module→action turn LED on, via configurationsand/or sensors;

via a reed switch, i.e. a lighting module (light guide) with on the endsa strip of magnetic material. On an inner side of the rail a Reed switchis located which will close the circuit that enables the LED that isdirectly below the switch;

masking, one way of getting the desired behavior (coupling light intothe lightguide and not being able to see light from the rest of thestrip) can also be achieved by turning on all the LEDs all the time. Tohide the light of the unused LEDs the LEDs can be masked e.g. by slidingplanes (in front of the LED) attached to a spring. By laying the opticalplate into the rail the mask would be (re)moved and the light would becoupled into the plate as it would line up.

Preferably sufficient LEDs are present to ensure that wherever themodule(s) are placed it can always be lit by at least one LED from oneside, more LEDs are better as homogeneity of light output is improvedthereby.

It should be noted that in the previous embodiment, all LEDs areconnected in series and that it requires additional measures to installmore than one module. Depending on the electronics setup it is possibleto use multiple modules in one rail. To attain this, in this embodiment,a capacitor is added to control the current via which the use multiplelighting modules on a track is enabled. The LEDs are grouped in pairsand connected in anti-parallel to a capacitor. Because the LEDs aredriven in AC mode the capacitor acts as an efficient current control.The lighting module now only needs to make a connection between a firstand a second contact point and everywhere where this connection is made,the LED pair will light up. This arrangement allows any number of LEDsto be connected. Such a lighting system with a parallel arrangement ofthe LEDs enables the use of a plurality of lighting modules.

An embodiment of the lighting system with the track comprising the lightsource is characterized in that at least one of the strips comprises atleast one PCB on which at least one LED is mounted. It is possible toslide the lighting module along the length of the strip and the LEDswill turn on and off as the module is moved. To get this abovementionedbehavior the system comprises a track and an optic plate, for example awaveguide plate such as PMMA, as the lighting module, the trackcomprising a first and second rail. The rails support the waveguideplate so that the plate can be laid into the space in between the tworails that make the track. In the side of the rails LEDs are placed ontop of a PCB also provided in the rails, and a mounted lighting modulemakes electrical contact with the electric conductive strips on the PCB.An embodiment of the lighting system is characterized in that the lightincoupling surface is the side face extending from the first sidetowards the second side and that facing towards said side face the LEDsare located on the rail at a respective rail wall extending from thecarrier side normal to plane P along the axis. The LEDs and PCBs arethen designed such that the LEDs line up exactly with the optic platemodules, i.e. the lighting module has a light incoupling surface facingtowards and opposite the light source. There are many different designpossibilities of the lighting module possible if the basic form of thelighting module is a light guide of which the edge aligns directly withthe LEDs in the strip. From that edge onwards there are countlesspossibilities. For instance:

1. A normal straight square plate of PMMA with light diffusing particlesmixed in homogeneously, for example known as EndLighten: EvonikACRYLITE® EndLighten, see also:http://www.acrylite.net/product/acrylite/en/products/sheet/endlighten/pages/default.aspx“Embedded with colorless light diffusing particles that cause light todiffuse forward, ACRYLITE® EndLighten acrylic sheet accepts lightthrough its edge and redirects it to the surface for bright, uniformillumination. ACRYLITE EndLighten T is a new material for powerfulambient lighting that is specially adjusted to transparent applicationsilluminated with LEDs. Unlike the familiar grade of ACRYLITE EndLighten,the new material shows no clouding and emits light at a much morevertical angle to the surface. In addition to its optimized frontallight output, ACRYLITE EndLighten T is highly transparent, even if nolight is fed into the material.”

The same lighting module as described in 1 but then provided with slitsthat have been laser cut into the wave guide plate material under a 45degree angle. This will reflect part of the light that has not beendiffused downwards (or downwards). This will cause the module to directmore light downwards than upwards at choice.

Many patterns of slits and structures can be designed. Slits preferablydo not extend over the whole width of the plate, as this will compromisethe stability of the plate.

If only one direction is desired a simple mirror, for example. MIROfoil, can be applied on one side. This will cause the light to haveroughly double intensity on one side.

If laser cuts inside the plate light are made, light that will hit theslit will change direction due to total internal reflection. When lasercuts are used the plate starts to behave as a spot as the light from thesides is re-directed into one direction.

The lighting module's wave guide plate can be formed out of the plane Pof the track, enabling a variety of 3D-shapes of the wave guide plate.

Various effects are attainable upon combination of the abovementionedpossibilities; for example, a wave guide plate made of EndLightenmaterial with laser cut slits will create a spot downwards and diffuselight in all directions.

An embodiment of the lighting system is characterized in that thelighting module has its electrical contacts at end parts that contactthe strips, in mounted position of the lighting module on the stripssaid electrical contacts at a first and a second contact point connectto respectively an anode and to a cathode contact strip provided in therails, to enable ignition of the (LED) light sources located in betweensaid first and second contact point. For example, on four corners, twocorners at each end of the lighting module, two pairs of “electriccontacts” are mounted. These contacts connect at one end of the lightingmodule the anode to the series of LEDs while at the other end thecathode is connected to the series of LEDs. The electric contacts aremade as a connector block of copper with two pins each. The two pins areat a distance to each other that corresponds with the distance betweenthe electric conductive strips on the PCB. The pins also provide for theforce necessary to make a proper contact between the different strips onthe PCB via the connector-block.

An embodiment of the lighting system is characterized in that said anodeand cathode are conductive strips extending along the length of therail, preferably located on a respective rail wall extending from thecarrier side normal to plane P along the axis. The profile of theconductive layer is designed such that all LEDs are connected in series.Above the row of LEDs there is an anode and a cathode electricconductive strip. Essentially said strips extend continuously from thebeginning to the end of the track/rail. The module consists of a plateof PMMA. The PMMA has been provided with diffusing elements, for examplethe optic plate is provided with light outcoupling pattern at at leastone of its first and second side, which is a relatively easy and cheapmethod to provide such diffusing elements, such that the lighting module(wave guide) appears transparent when no LEDs are turned on and it willlight up/become opaque and act as a diffuse light source when the LEDsare turned on.

Another embodiment of the lighting system is characterized in that theanode is located in the first and cathode is located in the second rail,and that the lighting module on transverse side faces that bridge thegap between the first and second rail and extend between the first andsecond side, is provided with connector strips to close an electricalcircuit and to enable ignition of the (LED) light sources that arecomprised in said circuit. In this embodiment, each rail of the trackhas an arrangement of LEDs, either an electrical plus or a minuselectrode, and a single electrical connection per rail. In this case theplus and minus need to cross the opening between the first and secondrail via the transverse sides of the lighting module. Rails of relativesimple construction are thus enabled.

In an alternative embodiment of the lighting device all the LEDs in therails are turned on all the time. By inserting the module the light isdirected into the module rather than somewhere else (e.g. down/upwardsor into an absorber). This embodiment is technically very simple andcheap, it is, however, relatively energy inefficient and therefore inmany cases not the best option.

A way to create a desired, more or less automated behavior of thelighting system is by actively detecting the lighting module andsubsequently acting upon said detection. Thereto an embodiment of thelighting system is characterized in that the lighting system comprises asensor. Sensors can be located in the module itself, in the track orseparate but close to the lighting system and can be used in differentconfigurations in the lighting system, for example:

Configuration 1: In this case the individual LEDs and individual sensorsare setup in a network and every LED and sensor has a predefinedposition and address. A CPU collects all the sensor information anddrives the LEDs;

Configuration 2: The LED and sensor are integrated into one package andaddressed. The CPU is interfaced with the LED-sensor combination throughthe addresses;

Configuration 3: The LED and sensor are integrated as well as theintelligence. This is an example of distributed intelligence. The basicembodiment is that when the sensor detects the edge of a lightingmodule, the LED turns on. In a more advanced embodiment the sensor isable to pick up additional information from the edge of the module suchas color and intensity information. Because of the embodied intelligencethere is only a Power line;

Configuration 4: A LED module comprises integrated intelligence and aseparate sensor. The rest is similar to Configuration 3;

Configuration 5: The sensor and intelligence are integrated into onepackage and the LED is connected to this sensor-intelligence (+driver)combination.

Different embodiments of detection of a module by a sensor areenvisaged. In this embodiment the lighting module comprises atransparent material (light guide) which is equipped with a small stripof material/painted on a layer on the side or on the top close to one ofthe edges of the module. This strip can be detected by the sensor.Thereto an embodiment of the lighting system is characterized in that asensor combination is selected from:

Reflective material+optical reflection sensor;

Magnetic strip+magnetic sensor, for example Hall sensor or Reed switch;

Electrical conductive strip+connectors, for example pins that connectgalvanic;

Conductive strip+capacitive sensor;

RF tags/transmitters in the modules and detectors/receivers in theLED/rail.

In more advanced forms these combinations also enable information to bepacked into the pattern of the strip. This information could give everyLEDs data on the light that is required at a particular place. Themethod by using the LEDs and the property of light-guiding can be usedto turn on the light. Even though most of the light should beout-coupled before it reaches the end of the light-guide some of thelight will reach the other end of the light guide and optionally can bedetected and used for further purposes. When the LEDs is provided withadditional light sensors or LEDs acts as light sensors, the LEDs sensewhether the optical plate is in front of the LEDs or not. The principleis then used that more light from the opposite LED reaches the opposingsensor/LED as sensor when it is guided through an optical plate ratherthan emitted into the environment in a rather broad beam.

Furthermore it is advantageous to periodically check the status of thelighting system and lighting modules. For example, every period everyLED would emit a predefined “Presence sequence”. When there is a nolight guide present the light would be emitted into all directions.However, when emitted into the light-guide more light would hit thesensor on the other side of the strip. Detection of this signal wouldturn on the LEDs on the opposite side. This method may not even requireopposite LEDs as part of the light emitted into the light-guide from onedirection will reflect back into the same direction because of thediffusing particles inside the material and the air-PMMA connection.

In particular in the case of LEDs as light sources, but also in the caseof point-like, compact discharge lamps and halogen incandescent lampshaving a relatively high power, for example 50 W HID or 75 W halogenlamps, heat management is an issue. Thereto an embodiment of thelighting is characterized in that the rails are embodied as heat sinksto dissipate heat generated by the lighting module.

To counteract this risk of corrosion of the conductive strips withaccompanying negative effect on power transfer from strips to lightingmodule, a second alternative of the lighting system is characterized inthat a spacing is present in between the rails and the electricalcontacts to enable capacitive power transfer (e.g. at 100 kHz), whichfurther has the advantage of safe, isolated (low) voltage, and that therails/strips can be painted to render the lighting system even moreunobtrusive.

As the electrical contact in the track based lighting system isinherently exposed to dust and open to corrosion, an embodiment of thelighting system is characterized in that the rails are protected by acoating, for example are coated with, for instance, paint oraluminum-oxide. For the electrical power transfer use is made ofcapacitive or inductive coupling, as in both methods a directmetal-to-metal connection is not required. An additional benefit of thecoated rails is of an aesthetical nature. Instead of “technical” lookingconductors, now coated rail track surfaces are visible which enable thetrack to either blend in or stand out from the environment. For example,alumina coated rails were connected to an HF electrical amplifier. Byusing the capacitance that exists between the rail and the lightingmodule and adding an appropriate inductance, a resonance circuit isattained. Driving it with roughly 50 kHz-500 kHz power could betransferred to the boat. To attain proper alignment between lightingmodule and the rail for good capacitive power transfer, the electricalcontacts of the lighting module are fixed to the base of the lightingmodule via flexible material, for example silicone rubber.

The electronics of the lighting module can be very simple, for example alighting module with a simple 4 diode-bridge and an inductor. The bridgecan even be omitted when two strings of LEDs are used that are connectedin opposite directions. In that case the strings will light upsequentially, but as this is done at high frequency, the sequentiallight-up that cannot be observed. Probably the thermal load will beidentical even at twice the current but half the time.

Various parameters have an effect on the efficiency of the lightingsystem. For example, the total power transferred is depending on whetherthe right resonance frequency is used. This frequency depends on thecapacitance of the ‘connection’. As this might be influenced by properpositioning or by excessive dust the system should be adjusted. This canbe done by proper aligning and removing the dust, but alternatively anembodiment of the lighting system according to the invention ischaracterized in that it comprises an automatic tuning circuit. Thisautomatic tuning circuit could for instance continuously check theamount of power transferred while changing the frequency slightly andthus finding the optimal frequency for improved and efficient powertransfer.

An embodiment of the lighting system is characterized in that thelighting module is equipped with rotatable wheels to enable the lightingmodule to ride over said track along the length axis. Another means forgalvanic connection is by using wheels like with trains. The wheels areattached to the sides of the module which would allow the module to bepowered from the rails through the wheels. This embodiment has theadvantage that the interaction of moving the lighting modules along thetrack is very smooth. Motors can be put into the lighting module ontothe wheels and that would enable the lighting modules to ride along thetrack, optionally via remote control. This can be useful in a dynamic‘light show’ or in multi-purpose rooms where the light settings needs tochange often. When the rail and the wheels are made such that theyattract each other due to the use of magnets the lighting module canalso be mounted to the strip upside-down, which however, is relativelyexpensive and therefore not preferred. To counteract the risk on mutualhigh impact collision of lighting modules, as a consequence of the verysmooth moving of the light modules along the track, an embodiment of thelighting system is characterized in that the lighting module is providedwith an anti-collision system, for example in that the lighting modulesare provided with repulsing magnet, for example only north-pole magnetsat the transverse sides of the lighting modules

An embodiment of the lighting system is characterized in that the lightsources are controllable, i.e. in that the characteristics of the lightissued by the light source is controllable on intensity (dimming orboosting), spectral composition as color and color temperature, and/orlight distribution. This enables the possibility to easily adjust theillumination level to a desired level, for example via a user interface,such as a remote control. It further enables an embodiment of thelighting system which is characterized in that the controllable lightsources have a receiver to receive input for setting a control level,for example by an occupancy sensor or by an external user interfacecommand, and have an activator to control the light characteristics ofat least one neighboring light source. A so-called “swarm intelligence”behavior of a group of lighting modules can thus be attained. Forexample situations with swarm intelligence light that could be obtainedand which leads to efficient energy use, are:

Lighting modules operating at full intensity only where needed, forexample where presence is detected;

Surrounding luminaires at medium intensity, hence no sudden drop inlight intensity between adjacent/neighboring lighting modules

Distant luminaires at low intensity, hence never completely dark areas.

The swarm intelligence concept therefore preferably involves featureslike:

The lighting module or group of lighting modules can detect a presenceusing an appropriate detector;

The lighting module can detect modulated light, for example by using aphotodiode;

The light emission of the lighting module is encoded for example byusing a certain frequency or digital code with the current operationstatus of the respective lighting module, for example

Detect daylight→stay off;

Detect presence→turn on with light setting 1, code 1, for example use of100% nominal power;

Detect code 1→turn on with light setting 2, code 2, for example use of80% nominal power;

Detect code 2>turn on with light setting 3, code 3, for example use of50% power;

Detect code 3→nothing;

Every lighting module reacts to its own presence detector and to thecoded light signal it detects from neighboring lighting modules.

The fact that an individual lighting module reacts to the behavior ofits surrounding lighting modules, results in a system like behavior ofall lighting modules, which is similar to a swarm of birds or fish whichseem to behave like a coordinated system or group. The lighting systemenables ample possibilities to sense the presence of ambient light andneighboring lighting modules, as the track has an opening between thefirst and second rail which enable the lighting module to emit lightboth upwards and downwards. Also different types light modules can bemade that allow light to be emitted under an angle and re-directable.Therefore this rail allows for multiple types of light modules (up anddown light for instance) and sensors can be integrated in the top andthe bottom of the module reaching an almost 360-degree sensing view.

To capture the value of the versatility of the lighting system, itpreferably ensures that a control system is in place that does notrequire difficult steps such as commissioning of new lighting modulesetc. The easy control of a flexible and potential large system can beguaranteed by using swarm intelligence, and for this reason swarmintelligence preferably is added to each lighting module. In that wayeach additional lighting module will behave as the other already presentlighting modules are behaving as well. The system will be robust and canbe enlarged without restraint. Thus, the lighting system clearly offersadvantage over a common known lighting, track based system. Its mainattractiveness is its versatility and ease of use. One can very easilychange the number and type of boats. Also the nature of the lightingmodules can be adapted by exchanging the lighting modules.

An embodiment of the lighting system is characterized in that at leastone, preferably all, of the lighting modules comprises a soft startcircuit. To facilitate a smooth and safe installation of additionalmodules, it is desired to equip each module with a “soft start” circuit.So at the instance when the module is connected to the system it doesnot consume or deliver a large amount of power, preventing sparks andother unwanted electrical effects. The soft start circuit is designed tolimit inrush current to a safe value. When the power source is switchedon, the initial current drawn from the mains is many times that, even atfull power. There are two main reasons for this, as follows:

-   Transformers will draw a very heavy current at switch on, until the    magnetic flux has stabilized. The effect is worst when power is    applied as the AC voltage passes through zero, and is minimized if    power is applied at the peak of the AC waveform.-   At power on, the filter capacitors are completely discharged, and    act as a short circuit for a brief (but possibly destructive)    period.

These phenomena are well known to manufacturers of very high poweramplifiers. The inrush current drawn is so high that other equipment isaffected. This high inrush current is stressful on many components inthe lighting system, for example on:

-   Fuses—these must be slow-blow, or nuisance fuse blowing will be    common-   Transformer—the massive current stresses the windings mechanically    and electrically.-   Bridge rectifier—this must handle an initial current way beyond the    normal, because it is forced to charge empty filter capacitors—these    look like a short circuit until a respectable voltage has been    reached-   Capacitors—the inrush current is many times the ripple current    rating of the caps, and stresses the internal electrical connections

The invention further relates to a track being suitable for use in thelighting system according to the invention, the track comprising atleast a first and a second rail mutually extending equidistantly alongan axis, said first and second rail are spaced apart by an openingdefining a plane P and the first rail comprises a first electricallyconductive strip and the second rails comprises a second electricallyconductive strip, said strips are mutually electrically isolated,wherein the track comprises a light source and comprises at least one ofa sensor and an additional detectable material. Embodiments of saidtrack have the characteristics of the track of the lighting system asdescribed in respective abovementioned embodiments.

The invention further relates to a lighting module being suitable foruse in the lighting system according to the invention, the lightingmodule comprising a first and second electrical contact adapted to makeelectrical contact with a respective one of the first and secondelectrically conductive strip when supported by a respective carrierside of both the first and second rail, and comprising a base having amutually opposing first and second side and wherein the lighting modulecomprises at least one of a sensor and an additional detectable materialextending over a first and or second (and not the transverse) side face.Embodiments of said lighting module have the characteristics of thelighting module of the lighting system as described in respectiveabovementioned embodiments.

FIGS. 1 and 2 schematically show respectively a perspective bottom viewand a top view of a first embodiment of the lighting system 1 accordingto the invention. The lighting system comprises a track 3 comprising afirst 5 and a second rail 7 extending mutually parallel along an axis orlength axis 9. The first and second rail are spaced apart by an opening11 lying in a plane P as defined by the parallel extending first andsecond rail. If the first and second rail are slightly curved, i.e. thatthe first and second rail together bend slightly out of a flat planeupwards or downwards, then the plane P is considered locally and followsthe curvature of the first and second rail. The first and second railshave a U-shaped profile in cross-section. Both the first and second railcomprise a respective conductive strip 13,15 which are isolated fromeach other and are provided at a respective rail wall 14 extending froma carrier side 6 of the rail normal to plane P along the axis.Alternatively, the conductive strips could be provided on a respectiveof the carrier sides itself. The lighting system further comprises alighting module 17, in the figure a power supply/a voltage powerconverter/a current source/a user interactive receiver plus controlmodule, having a base 19 with a first end 21 and a second end 23 thatare provided with a first 25 and respectively with a second electricalcontact 27 (see for example FIG. 4). In mounted position of the lightingmodule on the track, it rests on the carrier side of the rail and theelectrical contacts make electrical contact with the conductive strips.The base comprises a first 29 and second side 31 each provided at thefirst and second end with a respective groove 33 which in mountedposition grips around a part of the first respectively the second rail.The grooves are both present at the first and second side of the baseand on said both sides are provided with electrical contacts and enablethe lighting module to freely be shifted over the track along the axisand/or to be flipped around a horizontal axis and thus to be mounted ina reversed orientation. The first side comprises a first light emissionwindow 37 a with a first refractive (collimating) optical element 101 a,the second side comprises a second light emission window 37 b with asecond refractive (spreading) optical element 101 b. The first andsecond optical elements differ in color and refractive characteristics,the first and second light emission windows differ both in size andshape. Each light emission window is associated with a respective lightsource (not shown). Also a 180° rotation about a vertical axis ispossible. In mounted position the first side of the lighting module ispractically flush with the first and second rail, and rests solely withgravitation force on the track and is dismountable therefrom by a simpledisplacement of the lighting module in an upwards direction against thegravity direction 45. The opening is large enough to access the lightingmodule from by hand below for lifting the lighting module and to pass itthrough the opening and through plane P to below the track.

FIG. 3 shows cross sections of some rails of tracks 3 according to theinvention. The upper embodiment shows a first 5 and second rail 7 whichtogether form a wedge in cross sectional view, i.e. a V-shape from whichthe bottom part has been removed, thus causing the first and second railto be spaced apart by the opening 11. In the central embodiment eachrail 5,7 has an S- or Z-shaped cross section, which alternatively couldbe an L- or U-shaped cross-section. These shapes are relatively rigidwhich is favorable for elongated tracks as relatively few bridges (notshown) between the first and second rail are required to maintain thefirst and second rail in equidistant position. In the lower embodimentand viewed in cross-section, the first 5 and second rails 7 areconcavely curved towards each other enabling some variation in tilt of amounted lighting module on the track.

FIG. 4 shows a cross section of a second embodiment of the lightingsystem 1 according to the invention. In this embodiment the lightingmodule 17 comprises a light source 35, in the figure two LEDs, in thebase, which base 19 on its first side 29 has a light emission window 37through which, during operation, light is issued to below the track 3.The lighting module at its first 21 and second end 23 has resilientcontacts 25, 27 provided at a first 39 and second side face 41 extendingfrom the first side 29 towards the second side 31 of the base and restswith these resilient contacts on the rails 5,7 of the wedge-shaped track3.

FIG. 5 shows cross sections of a third embodiment of the lighting system1 according to the invention with the lighting module 17 being in ahorizontal position and in a tilted position with respect to the plane Pand opening 11. The side faces 39,41 of the lighting module are curvedand are each provided with a metallic electric conducting coating 25,27which act as electric contacts 25,27 of the module and whichelectrically connect to respective electric conductive strips 13,15provided on the rails 5,7. The frictional contact between lightingmodule and rails enable the lighting module to stay in a somewhat tiltedorientation (for aiming a light beam 43 issued at a tilting angle a withthe direction of gravity through the light emission window 37). However,when the tilting angle becomes too large, i.e. that an end 21,23 of thelighting module becomes positioned too close to the bottom part of oneof the rails, it will automatically slide back into a smaller, safertitling angle.

FIG. 6 shows an undulated version of the track 3 of the lighting systemaccording to the invention. The track comprises mutually, axiallyaligned first 5 and second rails 7 which together form an open,truncated wedge. Said wedge extends along the axis 9 as a consecutiveconnected sequence of insets 47, which insets are formed by pairs ofalternating inwardly 49 and outwardly bulging parts 51 of the first andsecond rail. The inwardly and outwardly bulging part of the first railbeing axially aligned with the inwardly and outwardly bulging part ofthe second rail, axially aligned in this respect means that the inwardlybulging parts of the first rail are positioned directly opposite to theinwardly bulging parts of the second rail. The same goes for theoutwardly bulging parts. The track thus formed has a shape similar to acaterpillar. The lighting module has a shape which matches with theshape of the insets. This type of track enables the track to be tiltedalong its length axis 9 and yet that lighting modules will not slidedownwards over the track but stay located in the desired inset.

FIG. 7 shows a first 1 a and a second lighting system 1 b being mutuallycoupled by a lighting module 17 according to the invention. In thefigure the lighting coupling module is in one part which more or lessrequires that the tracks of the first and the second lighting system arealigned, i.e. extend in the same plane P in the same direction along theaxis 9. P lies normal to the plane of the figure and parallel to theaxis. Alternatively the lighting coupling module is in two parts whichtwo parts are connected via a cable and which enables a much moreflexible mutual orientation and/or position between the first and secondlighting system.

FIGS. 8A-D shows two tilted positions for two embodiments of lightingmodule 17 on a track 3 of the lighting system 1 according to theinvention. FIGS. 8A-B relate to the same embodiment with a differenttilt of the lighting module and hence issuing a light beam atrespectively first α1 and second angle α2 with the direction of gravity45. To issue the beam at the relatively large angle α2, the tilt of thelighting module has to be relatively large, i.e. also α2, which in somecases could become too large. By providing the lighting module in itsbase with a light source pre-tilted at an angle α3, as shown in FIGS.8C-D, the direction of a light beam at an angle α2 requires only arelatively small tilt of the lighting module, i.e. α2-α3. To have thelight being issued at an angle al, the lighting module has to de tiltedat an angle α1-α3, which could be a relatively small negative angle.Rotation of the module of 180° over a vertical axis (about) parallel togravity, results in a similar, mirrored configuration.

FIG. 9 shows different shapes of 3D-shaped lighting modules in alighting system 1 according to the invention. In the light module 17 onthe left in the figure, the lighting module comprises a light guide 20part, in the figure made of PMMA, of a base 19 of the lighting module.The lighting module comprises light sources 35 at both the first 21 andsecond end 23 of the base 19 (shown in somewhat more detail in themiddle of the figure) of which, during operation, their generated lightis coupled into the light guide of the base. The light guide of the basecomprises a downwardly bulging part 53 to below the plane P. The bulk ofthe light guide material is provided with a light outcoupling structure55, in the figure light scattering particles, such that the bulging parthomogeneously issues light. The embodiment on the right in the figureshows light modules with a 3D faceted base. At each facet at least onelight source is located. A light distribution patterns or beam patternis obtained in dependency of the facet structure of the base, hence isvariety of light beam patterns is obtainable.

FIG. 10 shows a fourth embodiment of a lighting system 1 comprising alighting module 17 according to the invention in perspective and partlyin cross-section. The lighting system comprises a track 3 comprisingrails 5,7 with an L-shaped cross section. Each rail has a conductivestrip 13 (respectively 15) in its vertical rail wall 14 extending fromthe carrier side 6 normal to plane P along the axis 9. The carrier sideis provided with a slider profile 34 which is gripped around by thegroove 33 in the first side 29 of the base 19 of the lighting module tocounteract the lighting module to shift radially from the rails (andsubsequently fall down). The lighting module at its first 21 (and second23) end of its base has electrical contacts 25 (and 27) resilientlyseated via a spring 57 in a first 59 (and second 61) side face extendingfrom the first side 29 to the second side 31 of the base andelectrically contacts with resilient force the conductive strip of therail. Via the conductive strip and the resiliently seated electricalcontact the light source 35, in the figure a LED, is powered. Light fromthe light source is coupled into a light guide base part 20 of the baseand subsequently coupled out therefrom.

FIG. 11 shows a perspective top view of lighting system 1 comprising acapacitive coupled lighting module 17 flexibly mounted on the track 3.The rails 5,7 of the track are coated with an electrically isolatingcoating 67 (see also FIG. 12). The lighting module has at its first 21and second end 23 of its base 19 two copper plates as first 25 andsecond electrical contacts 27 which are flexibly connected to the base.The base itself is made from transparent silicone comprising anelectronic circuit 69 connected to the copper plates and comprising asimple 4 diodes bridge 71 and an inductor 73 connected to the lightsource 35. The diode bridge can be omitted when two strings of LEDs areused that are connected in opposite directions. In that case the LEDstrings will light up sequentially, but as this is done at highfrequency that cannot be observed.

FIG. 12 shows a coated track 3 suitable for capacitive energy transferto a lighting module (not shown). In the figure the track comprises twoalumina rails 5,7 painted with a greyish, electrically isolating coating67, in the figure a paint. The color of the paint can be chosen suchthat the track will stand out from or will merge into its background.The first and second rails of the track are coupled to each other viabridges 65, in the figure two bridges made of Perspex. The bridges aremutually positioned at relatively large axial distance which enablesample possibilities for free movement and positioning of the lightingmodules. Said bridges could simultaneously function as suspension meansfor the lighting system to be suspended, for example via cables, from aceiling.

FIG. 13 shows a perspective view of a part of a fifth embodiment of thelighting system 1 according to the invention during its operation. Thelighting system comprises a track 3 with L-profiled rails in 5 (and 7)which the light sources 35, LEDs in the figure, are located on the railwall 14 on a respective PCB 75. The LEDs and PCBs are designed such thatthe LEDs line up exactly with the light guide base part 20 (optic plate)of the lighting module. Above the row of LEDs there is an anode 13 a anda cathode conductive strip 13 b. The profile of the conductive strips isdesigned such that all LEDs are connected in series. The conductivestrips axially extend continuously from the beginning till the end ofthe track. The lighting module is carried by the carrier side 6 of therails. The lighting module comprises at each end 21 (and 23) twoelectrical contacts 25 (and 27), each electrical contact is made as ablock of copper with two resiliently seated pins 25 a,25 b (and 27 a,27b) each. The two pins per block are a distance to each other thatcorrespond with the distance between the conductive strips provided onthe PCB, see in particular FIG. 14 which shows a detail of a railprovided with the light sources mounted on a PCB of FIG. 13. The pinsalso provide for the force necessary to make a proper contact betweenthe different conductive strips on the PCB via the connector-block. Asshown in the figure, this configuration results in that only the LEDsare operating which are located in between the two electrical contactsper side face 39 (and 41). Light of the operated LEDs is coupled intothe light guide base part 20 and extracted therefrom via scatteringparticles embedded in the bulk material of the light guide base part. Asthe light guide base part has a light emission window 37 in both itsfirst 29 and second side (31), light will be issued both upwards anddownwards. Instead of light scattering particles in the bulk it isalternatively possible to provide the light guide base part with anoptical light extracting film, or a local light extraction pattern, forexample slits 55 as shown in FIG. 15, to extract the light.

FIG. 15 shows a bottom view of a lighting system 1 comprising a lightingmodule 17 with an alternative light guide base part 20 suitable for usein the lighting system of FIG. 13. The light guide base part is made ofoptically transparent light guiding material, such as PMMA, and isprovided with laser cut slits as light outcoupling structure (or lightextraction structure), see also FIG. 19 for more details on this. Manyalternative embodiments of the light guide base part are envisaged.

FIG. 16 shows an embodiment of the lighting system 1 in which the anode13 a and cathode electrically conductive strip 13 b are located in thefirst 5 respectively the second rails 7 and an embodiment of a lightingmodule 17 connecting these strips. In some cases it can be desired tohave a single electrical connection per rail. In this case the plus andminus need to cross the opening 11 between the rails via the module.Thereto the lighting module is provided with a first 77 and a secondconnector strip 79 on a first 81 respectively on a second transverseside face 83. Said first and second transverse side face of the lightingmodule extend between the first and second rail and bridge the openingbetween these rails. Only that part of the light sources 35 between thecontacts made by the connector strips, in the figure a first 85 andsecond LED-string part 87, will lighten up. One side of the track, forexample the first rail, has LEDs a plus electrode, while the other side,for example the second rail, has LEDs and a minus electrode. The firstconnector strip connects the plus electrode to the start of the firstand second LED string part located in the first respectively the secondrail. The second connector strip connects the minus electrode to the endof the first and second LED string part.

FIG. 17 shows an electric scheme for parallel mounted arrangement of aplurality of lighting modules 17 on the track. In the embodiment of FIG.16, all LEDs are connected in series and installment of more than onemodule requires additional measures. Thereto in the embodiment of FIG.17 an additional capacitor 89 is comprised in each of the electricalcircuits shown in FIG. 16 to take care of current control. The first 85and second LED string parts 87 are grouped in pairs 88 per lightingmodule and connected in anti-parallel to a respective capacitor. Becausethe LEDs are driven in AC mode the capacitor acts as an efficientcurrent control. The lighting module now only needs to make a connectionbetween point A and B, which connection is attained upon mounting of thelighting module on the track. Everywhere where this connection is made,the pair of LED string parts will light up. This arrangement allows anynumber of LEDs to be connected.

FIGS. 18A-B shows a cross-section of constructions of a reed-contact 91respectively constructions of a sensor 97 as located in the first rail 5(and second rail 7, not shown). In FIG. 18A the lighting module 17 isprovided on its first side face 59 with a band 95 of magnetic material.On the rail wall 14 of the first rail a Reed switch 93 is located. Thecombination of Reed switch and magnetic material forms a Reed contact.When the magnetic material strip and Reed switch are properly aligned,the reed switch will close the circuit that enables to lighten up theLED 35 that is directly below the switch. In more advanced embodimentsof the lighting system 1 this method of establishing (electrical)contact alternatively enables information to be packed into the pattern96 of the band. This information could give every LED information on the(type of) light that is required at that particular place. The lastmethod is by using the LEDs and the light-guiding property of the lightguide base part 20 of the lighting module. Even though most of the lightcoupled in at the first end 21 should be out-coupled before reaches thesecond end of the light-guide base part, a remainder of the light willreach the other end of the light guide. This remainder of light can besensed and the information on the strip can be read and be used toperform subsequent actions, for example to change the color of thelight.

FIG. 18C shows an electric scheme of the lighting system for control ofthe various lighting modules 17 or light sources 35 provided with arespective sensor 97 which enables to create a desired behavior of thelighting system 1 by actively detecting a respective lighting module andcreating a subsequent action to it. In the figure the individual LEDsand the individual sensors are setup in a network and every LED andsensor has a predefined position and address. The CPU 99 comprisesartificial Intelligence and collects all the sensor information, definesthe action between input and output and drives the LEDs.

FIGS. 19A-B shows both top views and transverse cross-sections (over thedotted line shown in the top view) of two different light guide baseparts 20 of lighting modules (17) for use in a lighting system with thelight sources located in the track. Many different lighting moduleembodiments are envisaged, for example similar light guide base partsbut then with light sources located at the first and/or second end ofthe base. The basic form of the lighting module is typically a lightguide of which the side faces 39,41 align directly with the LEDs in thetrack. There are countless possibilities of embodiments of the lightguide base part, for example a normal straight square plate of PMMA withlight diffusing particles mixed in homogeneously, or 3D shaped lightguide base parts (see FIG. 13 respectively FIG. 9).

The embodiments shown in FIGS. 19A-B have a light guide base part 20 ofEndlighten material, which comprises embedded colorless light diffusingparticles as part of the light outcoupling structure (not visible). Thelight guide base part further comprises as a part of the lightoutcoupling structure 55 slits that have been laser cut into thematerial at a 45° angle with the parallel first 29 and second side 31 ofthe base 19. This light guide base part made of EndLighten material willbe almost perfectly transparent until the LEDs are turned on. Then saidlight guide base part is a homogeneous diffuse light source if not lasercuts are made into said material. The laser cuts made inside the lightguide base part will cause light that hits the slit to be redirected andthus change direction due to total internal reflection. In FIG. 19A thiswill result in downwards reflection of the main portion of the lightthat has not been scattered. Through some diffusion by the scatteringparticle dope in the material a small portion of the incoupled light isscattered in all directions both upwards and downwards. This embodimentof FIG. 19A will result the lighting module to direct mainly lightdownwards and only little upwards and the lighting module is observed asto behave as a spot as the light from the sides is re-directed mainlyinto one direction. Alternatively, if only one main direction is desireda simple mirror, for example a MIRO foil, can be added to one side. Thiswill cause the light to be issued from the lighting module with aboutdouble intensity on one side compared to the intensity of light at theother side.

Many other patterns of slits and structures can be designed, for examplesee FIG. 19B in which the light guide base part, made of clear PMMA, isprovided with an alternating pattern of slits at angles of +45° and −45°with the parallel first and second side of the base. This light guidebase part provided with these laser cut slits in two orientations willcreate a spot downwards and a spot in upward direction.

Note that both in the embodiment of FIGS. 19A and 19B the slits do notfully extend from the first side to the second side or from the secondside to the first side, as this will compromise the mechanical strength,robustness and stability of the light guide base part. In order to getmost light redirected preferably three rows of slits are made.

FIG. 20 shows a perspective view of a sixth embodiment of the lightingsystem 1 according to the invention. The lighting device of the figureis suspended from a ceiling 101 via cables 63 attached to bridges 65which connect the first 5 and second rails 7 of the track 3 of thelighting system. Alternatively such a lighting system can be mounted ina recessed manner into a (false) ceiling 101. Via said cables thelighting system is electrically connected to the mains power source. Thelighting system comprises a plurality of lighting modules 17, four inthe figure, which can be freely shifted over the track along the lengthaxis 9. The track of the lighting system is rigid, such that it will notdeform under its own weight by which it suspends from the cables/bridgesand also will not deform under the load of the lighting modules. Thisembodiment of the lighting system is not feasible with lighting systemsin which the track is formed by a pair of equidistant electricconductive (metallic) cables as rails.

1. A lighting system accommodating a light source and furthercomprising: a track comprising at least a first and a second railmutually extending equidistantly along an axis, said first and secondrail are spaced apart by an opening defining a plane P and the firstrail comprises a first electrically conductive strip and the secondrails comprises a second electrically conductive strip, said strips aremutually electrically isolated, at least one lighting module comprisinga first and second electrical contact adapted to make electrical contactwith a respective one of the first and second electrically conductivestrip when supported by a respective carrier side of both the first andthe second rail, and comprising a base having a mutually opposing firstand second side, the lighting module and track being free from mutualoverhang to enable to dismount the lighting module from the track by adisplacement in a direction essentially perpendicular to plane P,wherein the track comprises the light source, preferably the lightingmodule has a light incoupling surface facing towards the light sourceand light outcoupling surface at its first side.
 2. The Lighting systemas claimed in claim 1, at least one of the rails comprises at least onePCB on which at least one LED is mounted.
 3. The Lighting system asclaimed in claim 1, wherein the lighting module is an optic plate,preferably made from PMMA.
 4. The Lighting system as claimed in claim 1,wherein the optic plate is provided with light outcoupling pattern at atleast one of its first and second side.
 5. The Lighting system asclaimed in claim 4, wherein the lighting module has its electricalcontacts at end parts that contact the strips, in mounted position ofthe lighting module on the rails said electrical contacts at a first anda second contact point connect to respectively an anode and to a cathodecontact strip provided in the rails, to enable ignition of the lightsources located in between said first and second contact point.
 6. TheLighting system as claimed in claim 1, wherein the anode is located inthe first rail and the cathode is located in the second rail, and thatthe lighting module on transverse side faces bridging the gap betweenthe first and second rail and extending between the first and secondside, is provided with connector strips to close an electrical circuitand to enable ignition of the light sources that are comprised in saidelectrical circuit.
 7. The Lighting system as claimed in claim 1,wherein the light incoupling surface is the side face extending from thefirst side towards the second side and that facing towards said sideface LEDs as the light sources are located on the rail at a respectiverail wall extending from the carrier side normal to plane P along theaxis.
 8. The Lighting system as claimed in claim 1, wherein at least oneof the rails comprises at least one reed and/or direct contact switch.9. The Lighting system as claimed in claim 1, wherein the lightingsystem is AC driven and that LEDs as the light sources are grouped inpairs and electrically connected anti-parallel to a capacitor.
 10. TheLighting system as claimed in claim 1, wherein the lighting systemcomprises at least one sensor.
 11. Lighting system as claimed in claim1, wherein the lighting system comprises a sensor and a detectablematerial, and that a combination of sensor and material is selectedfrom: Reflective material+optical reflection sensor; Magneticstrip+magnetic sensor, for example Hall sensor or Reed switch;Electrical conductive strip+connectors, for example pins that connectgalvanic; Conductive strip+capacitive sensor; RF tag/transmitter in themodule and detectors/receivers in the LED/rail.
 12. The Lighting systemas claimed in claim 1, wherein the lighting system comprises at leastone LED provided with a light sensor.
 13. The Lighting system as claimedin claim 1, wherein the lighting system comprises an automatic tuningcircuit.
 14. The Lighting system as claimed in claim 1, wherein thetrack has an elongated shape along the axis, the lighting module beingshiftable over said track along the length axis.
 15. The Lighting systemas claimed in claim 1, wherein the first and second rails are embodiedas heat sinks to dissipate heat generated by the lighting module.
 16. ATrack for use in the lighting system as claimed in claim 1, comprisingat least a first and a second rail mutually extending equidistantlyalong an axis, said first and second rail are spaced apart by an openingdefining a plane P and both the first and second comprises a first,continuously extending, electrically conductive strip and a secondcontinuously extending, electrically conductive strip, said strips aremutually electrically isolated, wherein the track comprises a lightsource and comprises at least one of a sensor and an additionaldetectable material.
 17. A Lighting module for use in the lightingsystem as claimed in claim 1, having two pairs of a first and secondelectrical contact at two corners of each end of the lighting moduleonly and adapted to make electrical contact with a first electricallyconductive strip and a series of light sources at a corner and with asecond electrically conductive strip and the series of light sources atthe other corner of each end when supported by a respective carrier sideof both the first and second rail, and comprising a base having amutually opposing first and second side and wherein the lighting modulecomprises at least one of a sensor and an additional detectable materialextending over a first and/or second side face.